There are some cases in which multiple storage subsystems are connected for storing data in a large-scale computer system. In these cases, if the restoration destination of the backup data is a specific storage subsystem, the load is concentrated, and it was difficult to reach the limit performance of the computer system.
One of the technologies for improving the restoration of the backup data is the technology of reducing and accelerating the restoration time (refer to Patent Document 1).
More specifically, if the same backup data is stored both in the disk and on the tape, this technology performs the restoration using the data stored in the disk to which high-speed access is possible, and achieves high-speed restoration. By the above-mentioned technology, high-speed restoration can be achieved.